Step 1

Gather all the ingredients. Please read and follow the black soybean package instructions. Some packages may say "soak overnight". My package directions say to soak 4-5 hours, so I soaked for 4 hours. For testing, I tried soaking the same brand of soybeans overnight, and the beans came out a bit too soft. So you may need to test to see how long you want to soak your beans.

Step 2

Gently rinse the black soybeans (kuromame) under cold water a few times. The skin is very fragile, so try not to damage. Discard any beans that are damaged. Drain well.

Step 3

Put the beans in the inner pot of Instant Pot. Add 4 cups of water to the pot and let them soak for 4 hours (or overnight, depending on your package instruction).

Step 4

To make the black soybeans even darker, we cook the black soybeans with rusty iron nails in Japan (Read more in the blog post). If you use rusty iron nails, clean 2-3 nails, wrap in a cheesecloth and add in the pot. Optionally, you can purchase purchase “Lucky Iron Fish" on Amazon and place it in the water.

Step 5

After 4 hours of soaking, put the inner pot back to the Instant Pot (keep the iron fish in the pot). Add 1 cup sugar, 2 ½ tsp soy sauce, and ½ tsp kosher salt. Mix well.

Step 6

Close the lid and set HIGH pressure for 15 minutes (It will take 10 minutes to pressurize). Make sure the steam release handle points at “sealing” and not “venting”. The float valve goes up when pressurized.

Step 7

When it’s finished cooking, the Instant Pot will switch automatically to the “Keep Warm” mode. Let the pressure release naturally, about 45 minutes. Open the lid and take out the inner pot and remove the iron fish.

Step 8

Pour the beans and sauce into a large airtight container. Let the beans cool uncovered.

Step 9

Kuromame are ready to eat, but to yield a more striking black color, let the beans soak in the sauce for at least a day. Cover and refrigerate. You can keep for up to a week in the refrigerator, or 1 month in the freezer.

Step 10

Drain the liquid and serve the kuromame. If you like to make it more festive, you can put gold leaf on top.

Step 11

Some use the leftover liquid to make Black Soybean Latte, some use the beans to make a pound cake and steamed cake, etc. I personally don't have leftovers as we all finish on during the New Year.